1. Technical Field
The present invention relates to a vehicle attitude controller suitably used for a vehicle, for example, a four-wheeled automobile.
2. Description of the Related Art
In general, the following vehicle attitude controllers are known. One of the vehicle attitude controllers calculates a lateral acceleration from a steering angle and a vehicle velocity of a vehicle and then differentiates the lateral acceleration to obtain a lateral jerk. A damping force of each suspension for each of front and rear right/left wheels is switched in accordance with the lateral jerk to reduce a roll rate (for example, see Japanese Patent Application Laid-open No. 2007-290650).
Another vehicle attitude controller obtains a target roll angle from a lateral acceleration obtained when a vehicle is running. After calculating a target pitch angle in accordance with the target roll angle, the vehicle attitude controller obtains a difference between the target pitch angle and an actual pitch angle so as to perform feedback control (FB control). In this manner, a target behavior of a vehicle body is realized so as to stabilize a vehicle attitude (for example, see Japanese Patent Application Laid-open No. 2007-170590).
On the other hand, still another vehicle attitude controller determines whether tires are present in a linear region (for example, a region in which a road-surface gripping state is good) or in a non-linear region (for example, a region in which the road-surface gripping state is bad) when the vehicle is running. When it is determined that the tires are present in the non-linear region, a damping-force characteristic is switched to a hard side to improve steering stability (for example, see Japanese Patent Application Laid-open No. 6-288876).